There was a piece in the paper the other day where some scientist had calculated the number of universes he thought there were. It was a nice manageable number- 13 or something like that- but totally random. Why 13 and not 14- or 42- or 107?

According to something else I read, alternate universes are formed every time a choice is made. You go to your favourite restaurant and immediately a number of universes come into existence- one for every item on the menu. In one universe you choose the pork, in another you have fish and chips, in a third you eat pie. If the choices don't have remarkable consequences the universes may collapse back into one another, but if the consequences are considerable- if for instance the pork makes you ill and the pie doesn't- they will stabilise and chug off on separate tracks- each one continually bifurcating as it goes.

If this is really how things are then the number of universes is infinite and there are millions of versions of you out there, all blithely pursuing their separate existences...

And every choice you make from that menu will give the kitchen staff choices to make, which in turn will generate even more alternate universes...

Even if similar universes would collapse back into each other it does seem that this train of thought would lead to the number of universes expanding exponentially to an infinite number.

Ultimately, though, I guess it doesn't matter if they exist or not; the mere possibilities of them is enough to demonstrate just how random our own universe is. And how every choice matters to some extent - but not necessarily in a way we can control.